1. Field of the Present Disclosure
The present disclosure relates to an image forming apparatus.
2. Description of the Related Art
An image forming apparatus supplies electricity to only one of plural toner density detection sensors in a development device unit side and causes the residual not to operate, and thereby reduces EMI (ElectroMagnetic Interference) noise.
For example, the toner density detection sensor oscillates to generate a detection signal with a frequency corresponding to a toner density using an oscillator circuit.
FIG. 3 shows a block diagram that indicates an example of a configuration of a typical image forming apparatus. For example, as shown in FIG. 3, when four detection signal are detected by oscillator circuits 111C, 111M, 111Y and 111K in sensors 101C, 101M, 101Y and 101K, and transmitted to a receiver-side circuit board 102 through four signal lines 102C, 102M, 102Y and 102K arranged side by side with each other, crosstalk occurs among the signal lines 102C, 102M, 102Y and 102K, and consequently causes respective frequencies of the detection signals, i.e. toner densities, not to be detected properly in the receiver-side circuit board 102.
In the aforementioned image forming apparatus, the development device unit side and a main body side that includes a controller are directly connected to each other using a connector, and therefore no signal lines are used between the development device unit side and the main body. Further, the aforementioned image forming apparatus performs switching electric power supply to the plural toner density detection sensors, and it may cause switching noise to occur at turning on/off of the electric power supply. Furthermore, until the oscillator circuits gets stable after starting the electric power supply, it is difficult to measure the toner densities properly.